The present invention relates to a new and improved construction of a roll or roller guide shoe for elevators or the like.
Generally speaking, the roll guide shoe of the present development is of the type comprising a plurality of travelling rolls which bear upon at least one guide surface of a guide rail and are arranged behind one another in the direction of elevator travel. The travelling rolls are rotatably mounted in at least one support or carrier element pivotably connected with a movable part of the elevator.
For the guiding of movable elevator parts, such as, for instance, elevator cabins and counterweights along guide rails, there have already been employed, as is well known in this technology, so-called slide or roll guide shoes. Roll guide shoes are particularly advantageous because the friction of the rolls in the static condition is only slightly greater than the rolling friction, and therefore, during transition of the movable elevator part from its stationary state into a mobile state it is possible to reduce to a minimum the arising jerky start-up movements.
According to a state-of-the-art roll guide shoe according to German Pat. No. 2,433,960 there are provided three roll pairs of the same construction. Each of the roll pairs bear upon one of three guide rail sides and each are pivotably mounted at a support or carrier element connected with the movable elevator part. Due to this arrangement there is imparted to the roll guide shoe the possibility of extensively compensating for irregularities, discontinuities and gaps at the rail joints in the guide rails, and thus, to reduce impacts and lateral movements of the movable elevator part.
An appreciable drawback of the roll guide shoe however resides in the fact that the rolls, which possess travelling surfaces which are elastic throughout certain limits, upon longer standstill of the movable elevator part, have imparted thereto at their contact locations with the guide rail at the roll circumference relatively pronounced flattened portions which are retained during further elevator travel over a longer period of time. These flattened portions cause an unquiet, jerky travel of the movable elevator part. This effect has found to be particularly disadvantageous in the case of so-called load frame elevators or lifts wherein the elevator cabin is suspended eccentrically and moves along guide rails arranged only at one side thereof. With this arrangement not only when the elevator cabin is loaded but also when it is empty are there transmitted relatively large forces by means of the roll guide shoe to the guide rails.